When a network service provider provides a service for a user in a communications network, quality of service needs to be taken into consideration to meet the user's requirement for service quality. With regard to this requirement, the 3rd Generation Partnership Project (3GPP) standards define a Policy and Charging Control (PCC) architecture. In the architecture, services can be detected, and quality of service (QoS) control and charging control can be performed on different services. In addition, the network service provider provides a value-added service, such as a firewall, network address translation (NAT), or video optimization, for the user on a Gi local area network (Gi-LAN).
A current network resource reservation procedure in the PCC mechanism defined in 3GPP is basically as follows: When user equipment (UE) accesses a service provided by an application function (AF), the AF sends an Rx session request to a policy and charging rules function (PCRF), where the request carries service information; the PCRF stores the service information, generates a control policy according to the service information, and delivers the control policy to a policy and charging enforcement function (PCEF); and the PCEF executes the network resource reservation procedure.
However, after a value-added service processor processes some value-added business services (such as a video optimization service) provided by the network service provider, network resources occupied by the processed services change. In the existing network resource reservation procedure, the PCRF still formulates a control policy according to the service information delivered by the AF by using an Rx interface, and sends the control policy to the PCEF, and the PCEF reserves a network resource according to the control policy. In this case, a network resource obtained by the user is a network resource occupied by the service before value-added processing, but not a network resource required by the service after the value-added processing. The reserved network resource is unrelated to an actual user requirement, which affects service experience of the user.